@b0rk I should have thought of this *before* you published (sorry) but the .. vs ... section reminds me of one: log and diff kind of disagree on which is which.

"git log foo..bar" shows changes on bar that aren't on foo, whereas "git log foo...bar" shows changes on _both_ sides.

But "git diff foo..bar" asks for a diff that shows foo stuff *and* bar stuff (one being removed, one added), whereas "git diff foo...bar" diffs against the merge-base, showing only the changes on the bar side.